1. (Field of the Invention)
The present invention relates to an idling return device for internal combustion engines and more particularly, to an idling return device for use with the throttle body of a carburetor or a mutipoint injection apparatus for internal combustion engines or to an idling return device for use with the throttle body for liquefied petroleum gas (LPG) internal combustion engines. The throttle body is provided with a throttle valve therein which is impelled by a return spring so as to be set at an idle opening.
2. (Description of the Prior Art)
As disclosed in the specification of Japanese Utility Model Publication No. 2663/1982, a conventional idling return device for internal combustion engines comprises a throttle body, a throttle valve provided within the throttle body, and a return spring for returning the throttle valve to a prescribed position. The return spring consists of a throttle valve return mechanism.
The conventional throttle valve is formed in such a manner that it is opened and closed in accordance with the accelerator pedal depressing force. Namely, the throttle valve having a throttle valve return mechanism consisting of a return spring, is formed in such a manner that the throttle valve returns (in the closing direction) toward an idle opening setting, as a result of the tensile force of the return spring when the accelerator pedal is no longer depressed.
However, when the return spring in a mechanism for returning the throttle valve by the action of the return spring is bent, the number of revolutions per minute of the engine crankshaft may become greater than a predetermined number even if the driver stops depressing the accelerator pedal. This may cause difficulty for the driver. Therefore, there has been a demand for a safety device for reliably closing the throttle valve when the driver stops depressing the accelerator pedal.